82 MISSOURI BOTANICAL GARDEN. 
recurvifolia and Y. flexilis are, suggests the possibility that 
the connecting varieties may really be of hybrid origin. 
Opposed to this supposition, however, are the absence of 
any recorded history of their source or origin; the fact 
that they have appeared in cultivation and are classed with 
plants likewise of garden origin or long cultivated and in 
their other forms giving evidence of considerable variabil- 
ity ; and, particularly, the facts that, except for Y. aloifolia, 
the Yuccas spontaneously fruit with extreme rarity away 
from their native home unless, as seems not to be the case 
in European gardens where these forms have made their 
appearance, a moth (Pronuba yuccasella) upon which their 
pollination almost absolutely depends has been introduced 
with them, and that most persons who have tried to fertil- 
ize the plants of this genus have met with little or no sus- 
cess. Still, suggestion of such hybrid origin has been 
made,* and the most positive proof is at hand that along 
the Mediterranean coast, at least, skilful operators can not 
only intercross these so-called species but can also hybrid- 
ize them reciprocally with other very distinct species both 
of the baccate and capsular sections of the genus. Thus, 
for instance, M. Deleuil, of Marseilles, in and subsequent 
to 1874, crossed Y. aloifolia variegata and Y. alba-spica 
(whatever that may be), Y. aloifolia variegata9 with Y. 
pendula (or recurvifolia), Y. plicata (or gloriosa plicata) 9 
with Y. angustifolia vera (or glauca), Y. plicata 9 with Y. 
X laevigata (=aloifolia variegata X alba-spica), Y. pli- 
cata9 with Y. filamentosa, Y. plicata 9 with Y. Treculeana, 
Y. cornuta (or Treculeana) 9? with various species, Y. 
aloifolia variegata 9 with Y. angustifolia vera, Y. gloriosa 
longifolia (or Y. flexilis glaucescens ?) 9 with various spe- 
cies, Y. xX laevigatag with Y. filamentosa, Y.cornuta and 
* Ellacombe, for instance, supposed the Y. Ellacombei of gardens, 
which I take to be synonymous with Y. gloriosa nobilis, to be a probable 
cross between Y. recurvifolia and the garden form known as Y. gloriosa 
superba. — Garden. 163 257. 
